Don't scroll to bottom in initial scrolling up of chatlogs.
Code cleanup.
Navigation manager for Waartaa.

This implements various utility methods around client side
routing in Waartaa, e.g., check if two paths belong to the
same page or not, is current page the first path to be loaded,
etc.
Added 'unbind' function to chatLogsWaypointHandler.
Add checks during shifting and unshifting items from pageStack

for a chat room.

- Don't unshift duplicate datetimes to pageStack array.
- Push items to pageStack even if it's empty.
Smoothly render new & old chatlogs

on initial load as well as on scrolling up & down.
Properly bind/unbind chatLogsWaypointHandler during routing.